Krell Full Power Balanced 600 power amplifier Wes Phillips January 1998

Wes Phillips wrote about the FPB 600 in January 1998 (Vol.21 No.1):

How does a pair of Mark Levinson No.33H monoblocks compare to the Krell Full Power Balanced 600, Stereophile's joint Amplification Product of the Year for 1997? After all, Martin Colloms went so far in his review last April as to claim that the Krell so rewrote the book on amplification as to require a total reexamination of Class A power amplifiers in Stereophile's "Recommended Components." I'm not sure I'd go that far, but Martin is essentially correct: Compared to the Krell, almost everything else sounds broken.

Directly comparing the FPB 600 and the No.33Hs proved a logistic nightmare. Both amps required extended warmup—ie, music playing through them for several days—before either reached its optimum. The upward climb was far shorter, of course, from powered standby. The problem stemmed from my house's wiring, which simply wasn't up to both amps sucking all that current through the same circuit. (That's it—my New Year's resolution for 1998 is to rewire the house with beefy audio-only circuits.) So my comparisons are not direct A/Bs of specific passages, but are the results of longer listening sessions separated by the requisite warmup periods. Flawed? Yes, but the best I could do under the circumstances.

Using Dynaudio Contour 3.3 and EgglestonWorks Andra loudspeakers, the differences between the amplifiers were subtle, very subtle. Both were essentially not there in terms of having an effect upon the music. And, while each was capable of kicking some major audio booty, the most impressive thing was that neither sounded like a big amp during the quiet passages. Both were delicate and graceful.

However, the Levinsons seemed to present low-level detail with less "light-against-black" spotlighting than did the Krell. Audiophiles frequently speak of silence as the "blackness" against which sounds are highlighted, but I think that most sounds appearing from silence are far less dramatic than that. In a sense, then, I'm calling the Levinson more natural-sounding for its lack of "added" drama—and I have to put "added" in quotes because that might be merely my preference. Another listener could as easily call the No.33H "duller," and laud the Krell for its ability to extract excitement.

Allied with that ability to portray low-level detail came a sense of natural ease; I found the Levinson ever-so-slightly more transparent in the midbass and low bass. This is the quality I alluded to earlier when I praised its ability to "float" low tones in the same manner as the highs. While the Krell has superb transparency down to its low midbass, it tends to favor muscle over subtlety in the deepest regions. Yet that seems too harsh a criticism of the FPB 600: it takes charge of the bottom end in a way few other amps ever have, while remaining very attuned to the musical moment.

As did the No.33H. I compared the two amplifiers using the first movement of the Masur/NYP Mahler 9 (Teldec 90882-2), recorded live in Avery Fisher Hall in April 1994 and chosen because of my familiarity with both hall and musicians. The Andante comodo begins extremely quietly, with a three-note syncopated rhythm in the cellos and horn (Myers again, sounding forth brassily). This must have had a deep meaning for Mahler—at the movement's climax he brings it back marked fff, h;dochste Kraft ("with the utmost force"). Mahler's friend, Alban Berg, called the riff "Death itself." God knows, it's forceful enough to qualify for such a frightening description.

Both amps handled the climax with ease. Both did superb jobs of conveying the emotion implicit in the intense wash of sound. But I felt the Levinson's clarity in the bass allowed me to hear the NYP double basses as distinct entities separate from, but still members of, the ensemble. The Krell certainly conveyed their power as members of the whole orchestra, but through the Levinsons I felt as though I could actually make out Eugene Levinson, Jon Deak, et al as individual players surrounded by air and anchored to the floor of the hall I know so well, playing in unison among another 100-odd players—all blowing, bowing, and banging furiously.

Comparing the two best amplifiers I've ever heard to one another, I reckon one has to be better. But if I seem uncomfortable in proclaiming the Levinson to be better than the Krell, I am—until I heard the No.33H, I never would have guessed the FPB 600 had an equal. These two amps are so close in character that another listener could very easily call it the other way. I can't imagine anyone being less than satisfied with either. Yet to my ears, no matter how slightly, the No.33H sounded like the better amp.—Wes Phillips